MIT Researchers Uncover Method For 3D Printing Electronics Without Semiconductors

Traditionally, active electronics—that is, devices that regulate electrical signals—are built using semiconductor-based transistors. These components are fabricated in controlled environments with processes that require billion-dollar facilities and specialised materials.

The MIT team turned this on its head. While working with extrusion 3D printing, they discovered that a copper-doped polymer filament exhibited a unique electrical property. When an electric current passes through, its resistance spikes dramatically. Then, when the current was removed, it reset.

It's this resettable resistance—something that's typically only found in semiconductors—that enabled the team to 3D print functional electronic switches. These switches can be used to create logic gates.

• 3D printing electronics creates devices that behave like transistors without silicon or advanced fabrication techniques.
• Unlike traditional electronics manufacturing, these devices can be 3D printed in a single step.
• Finally, instead of relying on expensive chip fabrication facilities, electronics manufacturing can take place in everyday settings—labs and businesses, for example, or even homes.

The researchers used standard 3D printing hardware and an affordable, biodegradable polymer filament infused with copper nanoparticles. Here's what makes it work:

• The filament is extruded through a nozzle to form conductive traces.
• When voltage is applied, the copper nanoparticles shift within the polymer. This increases resistance, albeit temporarily.
• Once the voltage is removed, the particles return to their original positions and resistance.

While these printed devices aren't competing with silicon chips anytime soon, they could be used for basic control and automation tasks, such as:

• Regulating electric motors
• Simple circuit protection
• Low-power computing applications

The MIT team plans to:

• Refine the technology to improve performance and explore other conductive materials
• Develop more complex circuits
• Experiment with printing entire electromechanical devices without any external components

According to Luis Fernando Velásquez-García, the lead researcher, the goal isn't to replace silicon chips—it's to expand what's possible with 3D printing.

"At the end of the day, all you care about is whether your device can do the task. This technology is able to satisfy a constraint like that." — Velásquez-García